User talk:Lexi Jenkins

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16 January 2016*Lexi Jenkins 16:35, 16 January 2015 (EST):

I am excited to work on all of the Biology 210 labs!


The Diversity of Life- 15 January 2015

Purpose: This week, we studied the concepts of natural selection and evolution. In order to show how certain traits in a population have changed over time, we needed to collect and study samples of biotic items found in nature. We came up with the hypothesis that the specimens found in different parts of the campus will contain different types of bacteria.

Materials and Methods: For this lab, we observed different types of Volvocine Line algae (Chlamydomonas, Gonium, and Volvox) under compound microscopes. We used droppers to drop the algae samples onto microscope slides and we used micrometers to measure the specimen. We used 50 milliliter sterile conical tubes to collect samples outside in specific niches. Then, we added 10-12 grams of the specimens to plastic jars and added 500 milliliters of water and .1 grams of dried milk to make Hay Infusion Cultures.

Data and Observations: When we observed the Volvocine Line algae, we were able to find 250 Chlamydomonas, 3 Gonium, and 2 Volvox. Only the Volvox has a specialization (spiked) and only the Chlamydomonas had a mechanism of motility (flagella). The Chlamydomonas was isogamous while the other two were oogamous. The Chlamydomonas were small, egg-shaped organisms, the Gonium were spherical, and the Volvox were spiked. In the niche (the school garden), we collected brussel sprout leaves and soil samples from several areas. There were a lot of biotic factors in that area. Here is our transect: Lab 1 Transect.jpg

Conclusions and Future Directions: The specimens collected in each niche all seemed to include different materials. This can mean that there are different bacteria and living things in each area, which could confirm our hypothesis when we observe the Hay Infusion Cultures.


Studying Algae and Protists-22 January 2015

Purpose: This past week, we learned how to identify different organisms based on a number of physical aspects. We also learned that dichotomous keys are important ways of identifying the nature of many organisms from different environments. We came up with the hypothesis that the different niches we collected samples from will contain different types of bacteria and biotic organisms.

Materials and Methods: For this lab, we continued to use the Hay Infusion Cultures we made last week. We observed the infusions in the jar then made two wet mounts (from the base of the jar and the surface) to observe them under compound microscopes. After that, we used dichotomous keys to identify as many organisms in the samples as possible. When this was done, we went on to the next part of the lab where we made dilutions of our cultures to observe what kinds of bacteria will grow in them over the next week. To do this, we labeled four 10 milliliter tubes of sterile broth. Then, we labeled four plates each of nutrient agar and nutrient agar plus tetracycline. We added 100 micrometers of the culture to the first 10 milliliter tube of broth using micropippetors, then took 100 micrometers of this dilution and added it to the next tube. This continued for all of the tubes, causing the final tube to be the most diluted. Finally, we plated the dilutions by taking 100 micrometers of each dilution in pipettes and spreading them.

Data and Observations: We ended up identifying arcella (pale, non-motile algae), actinosphaerium (clear, spherical, non-motile algae), stentor (cone-shaped, non-motile), and gonium (greenish, many celled) from the sample collected at the base of the culture container. At the surface of the culture, there were not many organisms, but we were able to identify euglena (motile, elongated, contains flagella). This could mean that the condition It was interesting to find several algae that were completely different from each other because all of the samples we collected from out niche were from the same general area and soil.

Conclusions and Future Directions: After completing this lab, we can conclude that within each niche, there is a plethora of organisms and algae that can be found. This supports our hypothesis we made at the beginning of the lab. Next time, I might compare the results we found to those of other groups to further examine the hypothesis.


Microbiology: DNA and Bacteria- 29 January 2015


This past week, we observed bacteria in agar plates to learn about antibiotic resistance and differences between bacteria. We also started observing how bacteria can be gram positive or gram negative. We came up with the hypothesis that there will be several species of bacteria present in the agar plates.

Materials and Methods:

To start the lab, we observed our Hay Infusion Cultures and paid attention to any changes in smell and appearance. Then, we collected our eight agar plates and counted the number of bacterial colonies present on them. After that, we scraped small amounts of growth from four of the plates with sterilized loops and made wet mounts to observe the bacteria under compound microscopes. At the same time, we made four gram stains by using the sterilized loops and mixing the growth with a drop of water. We used bunsen burners to dry the samples to the slides before soaking them in crystal violet, iodine, decolorizer, and safranin for certain amounts of time over a staining tray. Between each soaking, we rinsed the chemicals off with water. After that, we blotted the slides dry with kimwipes then observed them under compound microscopes. Finally, we made PCRs to isolate DNA in the bacteria. To do this, we had to 1)transfer a colony of bacteria into 100 microliters of water in a sterile tube, 2)incubate the tube in 100 degree Celsius water for 10 minutes, 3)centrifuge the tube for 5 minutes at 13,400 rpm, and 4)transfer 5 microliters of the supernatant from the centrifuged tube into the 16S PCR reaction tubes that were prepared while the sample centrifuged. The tube contained a mixture of 20 microliters of primer and water.

Data and Observations:

From our final observation of the Hay Infusion Culture, we learned that there was about half the amount of water as the day we made the cultures. Also, the color of the water was about the same but the smell was less pungent than the week before. When we observed the agar plates, we realized that the plates without the tetracycline had more colonies than those with it. This means that some of the bacteria was not resistant to the tetracycline, so they were unable to grow in the agar plates. We also noticed that the agar plates with the tetracycline made more fungus grow than the plates without the tetracycline. When we observed the gram stains, only one of the slides appeared to be gram positive, while the other three were negative. Each slide yielded different bacteria. One appeared to be Filamentous and the others were Fusobacterium, Vibrio, and Coccus. None of the samples were motile.

Conclusions and Future Directions:

Overall, there were species of bacteria discovered in the agar plates. This discovery supports our initial hypothesis that there would be several species of bacteria present in the agar plates.


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